Retort lining



COMPOSITIONS, F COATING 0R PLASTIC, Patented Mar; 10, 1936 I I I D S TThe present invention relates to material for lining retorts, stills,fractionators, and like appaw ratus in which high temperature, and oftenhigh pressure, hydrocarbon vapors are generated for the properfractionating of petroleum and for tilliie separation of sulphur, cokedparticles and the All retorts subject to pressure'require steel or ironin their structures and it is found that under the usual operatingtemperatures the impurities are highly corrosive, this beingparticularly true of the sulphur. H a a Again it is found that fine cokeparticles or free carbon particles are thrown out of the va pors andthese find their way into the most minute crevices of still linings.

A wide variety of linings are employed for this work and these naturallyprovide, or quickly develop, cracks which permit gases and coke par-vticles to enter. In this way, even if the lining succeeds in adhering tothe metal walls, sulphur vapors are free to reach and attack the ironwalls. Again the action of coke particles seems to be that ofcontinually crowding into the interstices and further acting to breakdown the lining.

Thirdly, some linings which are fairly satisfactory in other respects donot withstand the destructive action required when coke accumultions arebeing chipped off after a period of op-. eration. It is common practice,after hours of operation, for workmen to enter the retort and chip offcoke accumulations with chipping hammers. .It is therefore essentialthat the lining be capable of withstanding this action withoutdeveloping cracks which would subsequently admit sulphur to thesteelfwalls. s

From the foregoing it is apparent that a problem presents itself quitedistinct from that encoun-' tered with ordinary linings for resistingcorrosion of metal walls. Petroleum retort linings which are hard anddense at the outset readily crack. Others that meet some of therequirements do not withstand the action of chipping hammers when cokeaccumulations are being removed. Still others, which possess some of thenecessary characteristics cause the coke to combine with the structureof the lining in such marmer that the coke is not readily partedtherefrom and the lining is often badly damaged in attempts to removethe coke.

Again, linings which, under conditions other than those encountered inpetroleum retorts, are satisfactory, fail in the presence ofhydrocarbons which throw off fine coke or carbon particles.

2,033,644 an'ronrnmn za chimes L. Newport and Herbert G. Smith, ,1. 1 ,1Los Angeles, Calif.

No Drawing. Application September 15, 1933, Serial No.689,620. RenewedJanuary 29, 1936 4 Claims. (01. 196-133) i This is believed to be due tothe fact that these particles enter most minute crevicesand gen-' PATENT" erate destructive pressures which further en'- large the cracksuntil finally, both coke and sulphur find their way between the steelwalls and the lining.

It is the primary object of this invention to provide a retort lining,particularly for this class of work, which is resistant to acid andsulphur vapors; secondly which is economical and readily applied;thirdly which strongly adheres to steel walls and which after long usewill permit of coke accumulations being removed without cracking thelining; and fourthly which will withstand the usual temperature changeswithout loosening" or cracking.

- In addition to the foregoing requirements, it

is obvious that a long lived lining must adhere to the walls at allpoints in such manner that.

particles working into the structure of the lining will not build upbetween the lining and the steel wall of the retort and so act tocorrode the steel while loosening the lining.

Retorts for the fractionating of petroleum are of course lined when cooland it becomes another object of the invention that the lining bereadily applied. When the still is heated it is obvious that the metalwalls undergo expansion sulphur vapors or particles from passing thru itto the lining, and the final tensile strength and other physicalproperties essential for the successful removal of coke accumulationswithout damage.

Accordingly, in carrying out the present invention we provide a retortlining which possesses the qualities essential for convenientapplication and for successfully withstanding the initial conditions;the material used having the peculiar property of being acted upon bycertain elements in the petroleumto result in a new material possessingthe physical and chemical characteristics required to stand up under allusual conditions subsequently encountered.

In carrying out the present invention inone particular application weemploy a plastic mixture composed approximately 50% by weight of cementor binder and 50% by weight of a material or mixture comprising a highpercentage Per cent Portland cement by weight 50 Shredded mineral woolby weight 33.3 Diatomaceous earth by weight -16.?

These ingredients are mixed with .just enough water to produce a plasticmixture ready for application. Where added plasticity is required to aidin ready application asmall amount of clay particularly a gelatinousclay, may be added but care is always exercisedso that the clay will notreduce the voids of the finished material.

This mixture whenappliedto a steel surface in plastic condition will befound to adhere readily, although of course any of the usual expedientssuch as .wiremesh'may be used as a supporting element. The plasticmixture will be found to adhere closely. to metal walls both whenapplied and after it has dried.

Usually stills or retorts are down no longer than necessary and itisfound that heat can be applied to the still within 24 .hours afterapplication of the lining. Both during drying, as well as during theinitial application of heat, the lining is found to be suitablyresilient and does not crack or spall; this property being mostessential to final success.

When quite dry-however this mixture would not ordinarily possess therequired tensile strength, and tests prove-that it is not impervious togases. In the initial mixing of a batch the wool and diatomaceous earthbecomes dispersed thru the mixture in suchmanner that when it is set,the cement forms: a net-work of suitable strength, while, due to thecharacteristics of the wool and the diatomaceous earth the lining isrelatively porous and elastic while capable of acting as afilter forthefinest of coke particles.

Chemically the wool is practically balanced between the acid and basic,being-composed essentially of calcium and silica, in equi-molecularproportions. While the temperatures to which the lining is usuallysubjected in petroleum fractionating do not usually exceed 950 degreesF. the chemistry of the complete lining is believed to be important.

After the lining has been'in use, the linings are still intact aftermore than one year of use,

.it is found that the entire structure of the lining changes by reasonof the original lining becoming impregnated with carbon and sulphur.When so impregnated the lining has increased strength, and if such ispossible, adheres even more firmly to steel walls and becomes seeminglyan integral part thereof.

On the outer surface of this lining coked residue will build up in ahard formation which may be chipped away at intervals without damage tothe underlying lining, and a distinct cleavage is usually manifestbetween the lining proper and the incrustations which form.

While in the initially dried lining, before the retort is put intooperation, a cross section of as to absorb sulphur vapors, and theaccumulation of this foreign material in the interstices of the liningfinally results in a hard, dense and relatively impervious liningadhering firmly to the metal walls and finally excluding sulphur andother corrosive vapors from the steel surface to the extent that monthsof operation show no apparent corrosion. The lining thus formed is ofcourse highly resistant to the action of the very elements of which itis partially composed.

We are not limited to the specific ingredients or the specificproportions mentioned and we find that other ingredients and proportionswill carry out the invention, although we do find that mineral wool isideal for providing a suitably resilient structure and as an adsorbentfor coke and sulphur. The scope of our invention is therefore notlimited to the foregoing specific ingredients and proportions and samemay be varied within the scope of the appended claims without departingfrom the spirit of our invention.

We claim:

1. In combination with a petroleum processing vessel, a liningcomprising: a mixture of mineral wool and a cementitious binder soproportioned as to promote impregnation of the lining with particlesliberated from petroleum vapors undergoing a cracking process in .thevessel.

2. In combination with a petroleum processing vessel, a liningcomprising: a mixture of mineral wool, diatomaceous earth and portlandcement proportioned to promote impregnation of the lining with particlesliberated from petroleum vapors undergoing a cracking process in thevessel.

3. A combination of a petroleum processing vessel and a lining, thelining comprising a mixture of mineral wool and a cementitious binderimpregnated with coke particles.

4. A combination of a petroleum processing vessel and a lining, thelining comprising a mixture of mineral wool and portland cementproportioned to provide intersticial spaces for accumulation of solidparticles precipitating from petroleum being cracked in the vessel.

CHARLES L. NEWPORT. HERBERT 0. SMITH.

